The present invention relates to a large surface structural component, especially rotor blades or parts of such rotor blades, especially blade roots. Such large surface rotor blades are, for example, used in large scale wind energy collection equipment.
Rotor blades for so-called large scale wind energy collecting systems are primarily constructed of synthetic materials in order to achieve a lightweight structure and for other reasons, for example costs. According to a previously filed German Patent Application No. P 30 14 347.6-16 the blade shell is, for example, made of fiber reinforced synthetic material such as glass fiber reinforced material impregnated by synthetic resin. The blade core on the other hand is made of a hard foam material such as polyvinylchloride or the like. It has been found that with the increasing length of such components and with the increasing depth as measured from the leading edge to the trailing edge of the rotor blade, for example, substantial difficulties are encountered when efforts are being made to manufacture such components by employing time proven manufacturing techniques. This applies for the rather cost effective fiber winding method as well as to other conventional methods. The fiber winding method has already been employed in the construction of a helicopter rotor blade as disclosed in German Patent Publication (DE-OS) No. 26 11 235. No problems or difficulties are encountered as long as the structural component has dimensions within certain conventional limits. Such conventional limits are due to the conventional manufacturing methods which employ so-called negative molds for the manufacture of rotor blades. The use of such negative molds becomes rather prohibitive with regard to costs when it is necessary to produce large surface rotor blades or individual components of such rotor blades, especially when the surface configuration of such blades is complicated. Thus, it has, for example, been found that a rotor blade having a profile depth from the leading edge to the trailing edge of the blade of seven meters, the manufacture for example of the blade root by means of a negative mold, is economically unfeasible, especially if the blade root must have a cross-sectional contour which varies in its profile from the connecting end of the blade root to the blade section proper, for example, when the profile depth is to decrease from the blade end to the connecting end of the blade root.